August 7, 2012
A newly-released report by WWF and the Canadian Parks and Wilderness Society (CPAWS) reveals that the effects of climate change are reducing fish habitat on B.C.’s coast, threatening the province’s lucrative groundfish and shellfish fisheries.
The study is the first regional synthesis of its kind to document observed and expected impacts of a changing global climate on B.C’s marine ecosystems and to identify which parts are most vulnerable to climate change.
It reports that the Pacific Coast’s deep sea diversity is threatened and B.C. is losing two to three metres of deepwater habitat every year from oxygen depletion. “These oxygen depleted conditions are displacing fish and likely suffocating other sedentary species,” said Frank Whitney, an emeritus scientist at DFO’s Institute for Ocean Sciences, whose research contributed to the report. “This ought to be a significant concern to the groundfish fishery,” added Whitney.
Ocean acidification, likened to “osteoporosis of the sea” by the head of the National Oceanic and Atmospheric Administration, Dr. Jane Lubchenco, is another threat the report identifies. Increased intrusions of acidic water from deeper oceans are further expected to affect deep sea biodiversity such as deep sea corals, as well as more coastal species such as shellfish.
“Ocean acidification is already affecting commercial shellfish operations that now have to modify the pH of the ocean water they use to be able to raise shellfish in their tanks. We think that wild shellfish populations are also likely being affected by acidic water and may be not be successfully reproducing in some parts of the coast,” said Dr. Tom Okey, an Adjunct Associate Professor at University of Victoria’s School of Environmental Studies, who was the lead author of the report.
“Unlike Canada, other ocean countries such as Australia are actively building measures to monitor and reduce vulnerability to climate change in their marine plans and fisheries management,” said Sabine Jessen, National Manager of Oceans and Great Freshwater Lakes Program at CPAWS.
“Given the changes that are becoming apparent, it is critical that we are proactive here in B.C. and start looking at ways to reduce vulnerability of species and habitats from the impacts of climate change,” said Hussein Alidina, WWF’s senior officer for marine science and planning and co-author of the report.
Alidina says one action needed is to identify and protect “refugia” – areas that are sheltered or least-affected by changing ocean conditions where fish and other species can take refuge from climate change impacts as they adjust to changing conditions. These refugia should be part of BC’s network of marine protected areas.
- More incidences of southern species such as sardines and anomalous species such as Humboldt squid will be seen in BC waters. The ranges of Pacific salmon species, southern pink shrimp, Pacific cod and hake are among those shifting northward.
- Important spawning habitats for forage fishes such as smelt, sandlance and oolicahan that occur on soft sediment shorelines and other near shore habitats, will be lost to erosion if these habitats are not able to naturally migrate with rising sea-level because of coastal development or natural barriers. These species are key food sources to marine birds, whales and a host of other marine animals.
- Changes occurring in water temperature, glacier melt, rainfall and runoff will shift the timing of life stages and migration of species, including changes in the timing of the spring plankton bloom, will cause mismatches between predator and prey species.
- Regions that are heavily used for human activities and relatively more impacted will be much more vulnerable to the effects of climate change – this is particularly true of the Strait of Georgia/ Salish Sea.
The full report and Executive Summary are available at: http://assets.wwf.ca/downloads/cpaws_wwf_climate_report_1p.pdf .